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Piezoelectric nanogenerators (PENGs) have attracted great interest owing to their broad range application in environmental mechanical energy harvesting to power small electronic devices. In this study, novel flexible and high-performance double-layer sandwich-type PENGs based on one-dimensional (1-D) and two-dimensional (2-D) zinc oxide (ZnO) nanostructures and Ni foam as the middle layer have been developed. The morphology and structure of 1- and 2-D ZnO nanostructures have been studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). To investigate the effect of structural design on the piezoelectric performance, single-layer PENGs were also fabricated. The piezoelectric output of all prepared PENGs were evaluated under different human impacts at various forces and frequencies. The double-layer designed PENGs showed a two times larger voltage output compared to the single-layer PENGs, and the use of Ni foam as middle-layer and of 2-D ZnO nanosheets (compared to 1-D nanorods) was also found to increase the performance of the designed PENGs. The working mechanism of the prepared PENGs is also discussed. The design of nanogenerators as double-layer sandwich structures instead of two integrated single-layer devices reduces the overall preparation time and processing steps and enhances their output performance, thus opening the gate for widening their practical applications. [ABSTRACT FROM AUTHOR]

Polymer-based composites filled with ceramic particles such as barium titanate (BT) or lead zirconate titanate (Pb (Zr,Ti)O3) are considered as ideal materials for energy storage capacitors in electric systems. In this study, we fabricated poly (methylmethacrylate) (PMMA)/poly (vinylidene fluoride) (PVDF) composite films filled with a small amount (10 wt%) of BT by solution casting and investigated their dielectric properties. Our results indicate that the dielectric constants and breakdown strengths of the composites are strongly influenced by the mass content of PMMA. Furthermore, the composite film exhibits excellent energy properties (Ue, ~ 9.145 J cm−3; η, ~ 73.84%) when the mass ratio of PVDF and PMMA is 5:5. These composites possess significant potential as high-performance dielectric materials for energy storage capacitors. [ABSTRACT FROM AUTHOR]

Piezoelectric nanogenerators (PENGs) are the core components of self-powered devices used in sensors, ecofriendly wearable gadgets, and biomedical implants. This study introduces and demonstrates a flexible PENG with supersonically cold-sprayed films of cobalt titanate (CTO) and polyvinylidene fluoride (PVDF). An electrically poled PENG produces a maximum output voltage of 34.8 V under a tapping force of 20 N, whereas a CTO/PVDF-based PENG exhibits 25.4 V across a loading resistance ( R L ) of 50 MΩ and generates a short-circuit current of 30 μA at 0.1 MΩ. Furthermore, the maximum power density is 25 μW·cm-2 at R L = 0.6 MΩ. Cyclic tapping and bending test results show that open-circuit voltages (Voc) of 25.4 and 5.8 V are produced under the tapping cycle of N tap = 4200 and bending cycle of N bend = 750 , respectively, confirming the mechanical durability of the PENG. Thus, the potential of CTO/PVDF films for use in PENGs with various functionalities can be confirmed based on the V oc values generated from bending, mobile tapping, walking, and lifting movements. [ABSTRACT FROM AUTHOR]

The paper shows how different sintering methods affect the basic characteristics of PZT-type multicomponent ceramics. A perovskite-structured multicomponent ceramic of lead zirconate titanate (PZT) type doped with Mn4+, Sb3+, W6+, and Ni2+ and with a chemical composition of Pb(Zr 0.49 Ti 0.51) 0.94 Mn 0.015 Sb 0.01 W 0.015 Ni 0.03 O 3 was obtained. Ceramic powders were synthesized using the calcination method. Three sintering methods, including: (i) pressureless free sintering (FS), (ii) hot pressing (HP), and (iii) spark-plasma sintering (SPS), were used for the final sintering. The electrophysical measurements of the PZT-type ceramics, including scanning electron microscopy microstructure (SEM), X-ray diffraction (XRD), dielectric, ferroelectric, piezoelectric properties, and DC electrical conductivity, are presented. The microstructure of the samples is characterized by densely packed grains with correctly crystallized grain shapes but with different average grain sizes for each sintering technology used. At room temperature (RT), PZT ceramic samples have high values of resistivity ρ DC (from 7.25 × 108 Ωm to 1.14 × 109 Ωm), high values of permittivity (from 1048 to 1307), and low values of dielectric loss factor (from 0.008 to 0.02). Samples with the most favorable dielectric, ferroelectric, and electromechanical parameters were obtained using the FS and HP sintering methods. In the case of spark-plasma sintering (SPS), the assumed improvement in the electrophysical properties of the P-SPS ceramic sample was not obtained. Also, the most advantageous piezoelectric parameters have ceramic samples obtained by the FS and HP methods. The conducted tests verify that all the obtained ceramic compositions have a complete set of parameters suitable for micromechatronic applications. [ABSTRACT FROM AUTHOR]

Smart ferroelectric lead zirconate titanate (PbZr0.52Ti0.48O3) was synthesized in the morphotropic phase boundary by a sol-gel autocombustion strategy. The as-prepared powder was calcined at three different temperatures, 700, 800, and 900 °C for 3 h, each. The tetragonality of the final product increases with the rise of calcination temperature. Thermal gravimetric analysis and differential thermal gravimetric analysis depicted that complete crystallization of PZT was observed at 400 °C. Structural, vibrational, and microstructure studies were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy investigated for grains and elemental analyses and high-resolution transmission electron microscopy (HR-TEM). Results of XRD and HR-TEM were compatible, showing the formation of nanocrystalline powder with coexisting tetragonal and rhombohedral phases. Rietveld refinement of XRD data was carried out using material analysis using diffraction software in order to obtain the lattice constants. For mechanical and electrical measurements, disks were pressed at 10MPa. The samples were burned out at 500 °C for 1 h and then 1100 °C for 2 h to obtain more dense disks. The surfaces of the disks were coated with silver paste, followed by burning out for almost an hour. Dielectric and piezoelectric characteristics for the fabricated PZT samples were determined in detail. From these analytical techniques and collected data, one can deduce that the sample annealed at 900 °C can be used as an ultrasonic transducer in various metrological applications. [ABSTRACT FROM AUTHOR]

High‐power piezoelectric ceramics are typically driven to output vibration velocity (v0) under high AC electric fields. Herein, the Fe2O3 doped 0.125 Pb(Zn1/3Nb2/3) O3–0.075 Pb(Mn1/3Nb2/3)O3–0.8 Pb(Zr0.48Ti0.52)O3(PZMNZT–xFe; x = 0.05–0.35) piezoelectric ceramics were prepared to enhance v0, and the favorable comprehensive electrical properties, such as d33 = 315 pC/N, Qm = 1738, kp = 0.58, kt = 0.48, εr = 1156, tan δ = 0.4%, and Tc = 320°C, were achieved in the PZMNZT–0.15Fe ceramic. Most importantly, the PZMNZT–0.15Fe ceramic presented a reliable v0 of 0.90 m/s, which was 2.25 times of the commercial PZT4 ceramic (∼0.40 m/s). The excellent high‐power performance should be attributed to ordering functional elements such as crystal grains and ferroelectric domains. Overall, this work reveals that the PZMNZT–0.15Fe ceramic is competitive for high‐power applications. [ABSTRACT FROM AUTHOR]

Quasicrystals have aroused great interest and argument among researchers due to their unique atomic configurations. In this paper, based on the Stroh formalism and Barnett-Lothe matrices, we investigate the problems of two-dimensional piezoelectric quasicrystal composite wedges and spaces subjected to different loadings, such as line force and line dislocation. The special cases of the semi-infinite spaces, infinite spaces, and bi-material composite spaces are also taken into consideration. We derive the analytical expressions of displacements and stresses by considering the continuities of the displacements and surface tractions on the radial plane. After that, the comparative study regarding the infinite space problem, between solutions from Green's function and solutions from our method, is performed to verify the accuracy of the formulation and numerical results. Numerical examples are given to present the mechanical behaviors of quasicrystal under different loadings. The results prove that line force affects phonon displacement more clearly than phason displacement, but line dislocation affects stresses and electric displacement little. [ABSTRACT FROM AUTHOR]

PLZT (lanthanum-doped lead zirconate titanate) ceramic with outstanding photostrictive effect has been widely used in the micro precision drive field. In this article, a new closed-loop control method with ON-OFF control strategy is proposed for the photoelectric actuator based on PLZT ceramic. The closed-loop control model under driving voltage control strategy is established, and the parameters are identified by a series of experiments. Then, the control equations of driving voltage and output displacement of the photoelectric actuator are derived on the basis of the closed-loop control model during the light on and light off phases. After that, the numerical simulation analysis is carried out when the driving voltage and output displacement are taken as control objects respectively. According to the analysis results, the output displacement of the photoelectric actuator can be successfully controlled at a specific target value, and the proposed control method has excellent control effect, the feasibility and effectiveness of the control method are verified. Relevant conclusions can lay a foundation and provide theoretical guidance for the practical application of the photoelectric actuator in the field of active control. [ABSTRACT FROM AUTHOR]

The effect of the intrinsic properties of silicone rubber and barium titanate (BaTiO3) nanoparticles on the piezoelectric properties of BaTiO3/silicon rubber composites was studied by the finite element analysis. The data of the simulation show that the stress and voltage of the composite were greatly increased when the concentration of the BaTiO3 nanoparticle increased from 5 to 30 vol. %. As Young’s modulus of silicone rubber increased from 5 to 20 MPa, the compressive stress of the composites raised linearly. With the Poisson’s ratio rising from 0.41 to 0.49, the compressive stress increased by 0.18 MPa in the process. When the dielectric constant of the BaTiO3/silicon rubber composite was less than 30, the potential difference of the piezoelectric film gradually raised with the dielectric constant increasing. When the dielectric constant of the composite was higher than 30, the output voltage of the composite gradually decreased. Therefore, the lower Young’s modulus and Poisson’s ratio of the silicone rubber composite is beneficial to improve the piezoelectric properties of the composite. This article will provide a reference for designing the preparation of spherical BaTiO3 composite materials. [ABSTRACT FROM AUTHOR]

Health monitoring plays an important role in the maintenance of asphalt pavement. Tubular smart aggregate (TSA) is a cylindrical sensor composed of lead zirconate titanate (PZT) and protective coating. Ultrasonic waves are produced when the TSA vibrates and can be used to monitor the health of asphalt pavement. The influence of the protective coating material of the TSA, elastic modulus of PZT, and diameter of the TSA on the TSA resonant frequency was studied. A voltage signal and mechanical load were applied to the TSA; vibration and the received voltage of the TSA were collected. Furthermore, two TSAs were embedded in an asphalt mixture to transmit and receive ultrasonic waves. The vibration and generated voltage by the TSA embedded in the asphalt mixture were collected. Results indicate that the resonant frequency of the TSA increases with the increase of the elastic modulus of protective coating and PZT. With the increase of the diameter of the TSA, the resonant frequency of the TSA decreases gradually. When the voltage signal and mechanical load subjected to the TSA were close to the resonant frequency of the TSA, larger vibration and voltage were generated. Due to the viscoelasticity of the asphalt mixture, the resonant frequency of the TSA embedded in an asphalt mixture was reduced. [ABSTRACT FROM AUTHOR]

A composition-dependent structural, microstructure, ferroelectric, and energy storage performance of novel barium-based (1 − x)Ba(Zr0.1Ti0.9)O3 − x(Ba0.85Ca0.15)TiO3[(1 − x)BZT − xBCT] pseudo-binary systems with x = 0.0, 0.3, 0.5, 0.7 and 1 are investigated systematically. The barium zirconate titanate, BZT (x = 0.0), and barium calcium titanate, BCT (x = 1) ceramics exhibited a single-phase rhombohedral (R) and tetragonal (T) perovskite structure, respectively. The derivative of [(1 − x)BZT − xBCT] compositions with x = 0.3 enters into the orthorhombic phase (O), and the other two compositions with x = 0.5 and 0.7 compositions enter into the tetragonal phase. The surface morphologies reveal dense, uniform grain size varies from 2.59–12.05 μm with the addition of BCT to the BZT matrix. The presence of all the elements is confirmed using EDX analysis, and the existence of both Ti4+ and Ti3+ valence states in the Ti core level found in the sample. The maximum polarization is 15.06 μC/cm2 achieved for the x = 0.3 sample at 15.50 kV/cm applied field. The recoverable energy density (Wrec) and energy efficiency (η) are estimated to be nearly 167 mJ/cm3 and 42%, respectively. These outstanding characteristics of [(1 − x)BZT − xBCT] ceramics are ascribed to polymorphic phase boundaries, demonstrating their superior ferroelectric and optical properties. The present study may pave a new path in designing dielectric ceramics through intermixing MPBs for energy storage and multifunctional electro-optical devices. [ABSTRACT FROM AUTHOR]

This study explores the effects of filler concentrations of lanthanum-doped lead zirconate titanate (PLZT) on the electrical and mechanical characteristics of nanocomposite thick film. Crystal structure and morphology of the thick film have been studied using X-ray diffraction, atomic force microscopy, and scanning electron microscopy techniques. It has been noted that adding PLZT nanoparticles to the polyvinylidene fluoride (PVDF) matrix modifies the physical properties of PVDF. In the nanocomposite film, the most prominent polar β phase has been identified at 6 mol% of PLZT filler. In all the films, a nearly homogenous grain distribution has been observed. Frequency-dependent dielectric, conductivity, and impedance of the sample were studied at room temperature. Maximum electric dipole polarization of 0.68 μC/cm2 and piezoelectric (d33) constant of 48 pC/N have been observed at 6 mol% of PLZT filler in the PVDF matrix. Indeed, it has been observed that the (0.94)PVDF–(0.06)PLZT nanocomposite film is well suited for applications such as nanogenerators, structural health monitoring systems, and various kinds of sensors and actuators. [ABSTRACT FROM AUTHOR]

Flexible wearable sensing devices are in great demand for self-powered systems. In this study, we fabricated fiber films of poly(vinylidene fluoride) (PVDF) matrix embedded with modified lead zirconate titanate nanoparticles (PZT NPs) using the electrospinning process. Each fiber film was cut into small pieces of 2 × 2 cm2, and pairs of pieces were pressed with a hot-pressing method. Modified PZT NPs with a high piezoelectric coefficient were embedded in PVDF fibers as a piezoelectric-reinforcing phase, which promoted the formation of the polar β phase in PVDF. The embedded PZT NPs affected the distribution of the polarized electric field and formed a local electric field between two PZT NPs, which promoted the polarization of PVDF, thereby enhancing the piezoelectric properties of PVDF/PZT NPs fiber films. The piezoelectric coefficient (d33) of the PVDF/PZT NPs fiber films embedding 4 wt.% PZT NPs showed the most significant enhancement, from 12 pC/N for neat PVDF to 21 pC/N, which is an approximately 75% improvement. The results of this work demonstrate the great potential application of piezoelectric composite fiber films in flexible wearable sensing devices. [ABSTRACT FROM AUTHOR]

Ferroelectric materials exhibit spontaneous polarization that can be switched by electric field. Beyond traditional applications as nonvolatile capacitive elements, the interplay between polarization and electronic transport in ferroelectric thin films has enabled a path to neuromorphic device applications involving resistive switching. A fundamental challenge, however, is that finite electronic conductivity may introduce considerable power dissipation and perhaps destabilize ferroelectricity itself. Here, tunable microwave frequency electronic response of domain walls injected into ferroelectric lead zirconate titanate (PbZr0.2Ti0.8O3) on the level of a single nanodomain is revealed. Tunable microwave response is detected through first-order reversal curve spectroscopy combined with scanning microwave impedance microscopy measurements taken near 3 GHz. Contributions of film interfaces to the measured AC conduction through subtractive milling, where the film exhibited improved conduction properties after removal of surface layers, are investigated. Using statistical analysis and finite element modeling, we inferred that the mechanism of tunable microwave conductance is the variable area of the domain wall in the switching volume. These observations open the possibilities for ferroelectric memristors or volatile resistive switches, localized to several tens of nanometers and operating according to well-defined dynamics under an applied field.

Bismuth-based piezoelectric ceramics are presently of immense interest to researchers as they are believed to be Pb-free alternatives to well-known lead zirconate titanate-based piezoceramics. Herein, the author reports a lead-free ternary solid solution (1−2x)Na0.5Bi0.5TiO3-xBaTiO3-xBa0.7Ca0.3TiO3 (x = 0.01, 0.03, 0.05, 0.07, and 0.09: BNT-BT-BCT) synthesized through a standard solid state reaction route. All the samples crystallized to a complete perovskite structure studied through the powder x-ray diffraction analysis. Rietveld analysis of x-ray diffraction data revealed a structural transformation from monoclinic (Cc) to tetragonal phase (p4mm) with the co-existence of monoclinic (Cc) and tetragonal (p4mm) phases in the samples of x ≥ 0.03. The temperature-dependent dielectric analysis of (x = 0.03 and x = 0.05) systems suggests relaxor characteristics near ferroelectric–antiferroelectric phase transition temperature (Td). A changeover from relaxor to a near normal ferroelectric character was realized for x ≥ 0.07. Furthermore, the existence of polar nano-regions (PNRs) was studied through HR-TEM. Interestingly, a low electric field (±25 kV/cm) driven enhanced piezoelectric [(with 0.22% of strain; Smax/Emax = 850 pm/V for x = 0.03) and (with 0.17% strain and Smax/Emax of 714 pm/V for x = 0.07)] and an electrostrictive [with 0.20% of strain; Smax/Emax = 820 pm/V for x = 0.05] was achieved around Td. This can be attributed to the combined effects of phase boundary, ferroelectric–antiferroelectric transition, and the existence of PNRs. [ABSTRACT FROM AUTHOR]

The article discusses the importance of energy in sustainable development and the need for research and development in energy conversion systems. It highlights the limitations of current energy systems and the goal of achieving sustainable and environmentally friendly energy solutions. The article also provides an overview of a research topic on recent developments in energy conversion systems, including papers on topics such as piezoelectric materials, corrosion control methods, lithium-ion batteries, renewable off-grid mini-grids, and materials for fuel cells. The research topic has received positive responses and has generated significant interest. The article concludes by emphasizing the importance of ongoing research for a more sustainable and energy-efficient future. [Extracted from the article]

In this work, we report a systematic study of complex La3+ and Sc3+ doped lead zirconate titanate ceramics with the stoichiometric formula (PbZr0.53Ti0.47)0.90 (LaxSc1−x)0.10O3−δ for x = 0.2, 0.4, 0.6, and 0.8 denoted as PLZTS2, PLZTS4, PLZTS6, and PLZTS8, respectively (abbreviated as PLZTS10x), synthesized using the solid-state reaction method. We carried out dielectric measurements on Ag/PLZTS10x/Ag metal–ferroelectric–metal capacitors as a function of temperature (100–650 K) and frequency (102–106 Hz). Upon increasing La3+ concentration, the dielectric constant was found to be increased up to x = 0.6 and attained the highest value of ∼1800 at room temperature, and consequently, the highest saturation polarization was observed. The relaxor behavior of PLZTS8 can be attributed to the polar nano regions created in the materials. A recoverable energy density of ∼1162 mJ/cm3 with an excellent efficiency of ∼79% was achieved under an applied electric field of 97 kV/cm. The demonstrated high dielectric constant (ɛ′), spontaneous polarization (Ps), and energy density make these bulk materials promising for ferroelectric memory and energy-storage applications. [ABSTRACT FROM AUTHOR]

Several high-explosive (HE) crystals are known to be piezoelectric. However, no systematic study has been carried out on how this effect can be utilized. In this paper, we report the results of an analysis on the response of composites consisting of HE crystals and a polymeric binder under electrostatic excitation. The HE crystals considered are 1,3,5-trinitroperhydro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, pentaerythritol tetranitrate, and ammonium perchlorate. To explore avenues for enhancing the piezoelectric effect, the binder of the composites is taken to be piezoelectric polyvinylidene fluoride. The focus is on the distributions of induced electric field vector and mechanical stress in the microstructures. The effects of crystal–binder volume fraction, HE crystal size, and dielectric constants of the HE crystals are investigated. To further explore the effect, microparticles of lead zirconate titanate piezoelectric ceramic are introduced to some microstructures. For the HE crystals considered here, a coupled electromechanical analysis shows that the microstructural heterogeneities can enhance the local electric fields to as high as 1.34 times the applied E-field, causing the dielectric breakdown field strength of the overall composite to be much lower than the breakdown strengths of the constituents in the microstructure. In addition, the induced stress levels just prior to dielectric breakdown are well below the yield strengths of the respective constituents. As such, controlled dielectric breakdown, rather than mechanical damage, should primarily be used to facilitate hotspot formation, ignition, and chemical reaction. The likelihood of local dielectric breakdown within the HE crystals is systematically quantified as a function of applied electric field, microstructural attributes, and constituent behavior. To gauge the effect of the direct piezoelectric effect, one material case is also subjected to mechanical excitation in the form of compression. Under an applied external stress, the results show that the direct piezoelectric effect can lead to local yielding and thereby serve as a hotspot generation mechanism. On the other hand, the induced E-field is weak and unlikely to serve as a practical or efficient means of effecting hotspots within an energetic material. The analysis points out that simultaneous application of electrostatic excitation and mechanical excitation can also be considered. [ABSTRACT FROM AUTHOR]

10.1063/5.0044758 82 M. Makarovic, M. Ç. Bayir, H. Ursic, A. Bradesko, and T. Rojac, "Domain wall conductivity as the origin of enhanced domain wall dynamics in polycrystalline BiFeO3", J. Appl. Phys. 10.1063/5.0029582 79 D. Zhang, D. Sando, Y. Pan, P. Sharma, and J. Seidel, "Robust ferroelectric polarization retention in harsh environments through engineered domain wall pinning", J. Appl. Phys. Today, it is established that ferroic domain walls represent outstanding functional nano-entities with unique physical properties, which are exploited in the rapidly expanding field of domain-wall nanoelectronics.[[16], [23]] Due to their low local symmetry and the distinct structural, electric, or magnetic environment, ferroic domain walls can behave substantially differently than the surrounding domains. Ferroic materials exhibit long-range order with respect to their elastic, electric, or magnetic properties, giving rise to fascinating physics and functional properties that are used in, e.g., state-of-the-art sensor technology, energy harvesting, and medical diagnosis. [Extracted from the article]

Nanoparticles, films, and patterns are three critical piezoelectric elements with widespread applications in sensing, actuations, catalysis and energy harvesting. High productivity and large-area fabrication of these functional elements is still a significant challenge, let alone the control of their structures and feature sizes on various substrates. Here, we report a fast and versatile electrostatic disc microprinting, enabled by triggering the instability of liquid-air interface of inks. The printing process allows for fabricating lead zirconate titanate free-standing nanoparticles, films, and micro-patterns. The as-fabricated lead zirconate titanate films exhibit a high piezoelectric strain constant of 560 pm V−1, one to two times higher than the state-of-the-art. The multiplexed tip jetting mode and the large layer-by-layer depositing area can translate into depositing speeds up to 109 μm3 s−1, one order of magnitude faster than current techniques. Printing diversified functional materials, ranging from suspensions of dielectric ceramic and metal nanoparticles, to insulating polymers, to solutions of biological molecules, demonstrates the great potential of the electrostatic disc microprinting in electronics, biotechnology and beyond. In this work, authors demonstrate a fast and versatile microprinting technique to produce high-performance and customizable piezoelectric elements by employing a conductive spiny disc to electrostatically trigger instability to the liquid-air interface of the ink. [ABSTRACT FROM AUTHOR]

Perovskite ferroelectric thin films exhibit unique dielectric and piezoelectric properties owing to their internal polarized domains that accommodate the out‐of‐plane (ferroelectric) and in‐plane (ferroelastic) polarization‐induced electrostatic and elastic energy. These domains are generally treated as 2D defects with distinctive differences in domain morphology and domain‐wall characteristics, although they are indeed 3D volumetric defects. Here, by using atomistic simulation and microscopy characterization, a "pseudo‐ferroelectric domain" that has the morphology similar to a ferroelectric domain but holds the same defect character of ferroelastic domain‐wall, i.e., semi‐coherent (100)matrix||(100)domain interface is identified. Such pseudo‐ferroelectric domain walls will play a critical role in the migration kinetics of ferroelastic domains and in the piezoelectric responses of ferroelectric thin films during cyclic mechanical/electrical loading. The study throws light on a novel aspect of domains, namely, the 3D configuration and mobility of domain walls, and their role in the overall domain engineering. [ABSTRACT FROM AUTHOR]

Soft materials that can produce electrical energy under mechanical stimulus or deform significantly via moderate electrical fields are important for applications ranging from soft robotics to biomedical science. Piezoelectricity, the property that would ostensibly promise such a realization, is notably absent from typical soft matter. Flexoelectricity is an alternative form of electromechanical coupling that universally exists in all dielectrics and can generate electricity under nonuniform deformation such as flexure and conversely, a deformation under inhomogeneous electrical fields. The flexoelectric coupling effect is, however, rather modest for most materials and thus remains a critical bottleneck. In this work, we argue that a significant emergent flexoelectric response can be obtained by leveraging a hierarchical porous structure found in biological materials. We experimentally illustrate our thesis for a natural dry luffa vegetable-based sponge and demonstrate an extraordinarily large mass-and deformability-specific electromechanical response with the highest-density-specific equivalent piezoelectric coefficient known for any material (50 times that of polyvinylidene fluoride and more than 10 times that of lead zirconate titanate). Finally, we demonstrate the application of the fabricated natural sponge as green, biodegradable flexible smart devices in the context of sensing (e.g., for speech, touch pressure) and electrical energy harvesting. [ABSTRACT FROM AUTHOR]

This paper presents an application of Legendre polynomial approach to solve the wave propagation in a piezoelectric ZnO planar resonator subjected to stress-free boundary conditions and excited using two thin electrodes connected to an electrical source. The method is able to take into account the boundary conditions, the presence of electrical source and the different dissimilarities of the physical properties. Resonance frequencies of longitudinal modes are calculated in case of an open and short-circuit brunch. Dispersion characteristics are also calculated such as mechanical displacement and stress profiles for different resonance frequencies. The electromechanical coupling coefficient is also calculated. [ABSTRACT FROM AUTHOR]

Single-phase ceramic samples of new compositions (Na1 –хSrх)0.5Bi0.5TiO3 (x = 0–0.5), including those modified by additives of SiO2 and ZnO oxides, have been obtained by solid-phase synthesis. The crystal structure and microstructure of these samples, as well as their dielectric, nonlinear optical, and local piezoelectric properties, have been studied. The formation of a perovskite-type phase with a pseudocubic unit cell in all synthesized samples and an increase in the cell volume as a result of partial substitution of perovskite structure cations are established. A decrease in the temperature of ferroelectric phase transitions (confirmed by the methods of dielectric spectroscopy and laser second-harmonic generation) to the tetragonal paraelectric phase is revealed. Remanent piezoelectric hysteresis loops are obtained for the synthesized samples in the polarization switching mode; this result confirms the occurrence of ferroelectric polarization switching. [ABSTRACT FROM AUTHOR]

A lead‐free tetragonal‐phase (Ba0.94Ca0.06)(Ti0.95Zr0.05)O3 (BCTZ) micro sheet is prepared by molten‐salt growth method, which exhibits a polarizing behavior of relaxor ferroelectricity and possesses a high dielectric constant (εr) of ~2400. Subsequently, the BCTZ sheet is evenly doped into ferroelectric copolymer P(VDF‐TrFE)55/45 mol% with different mass fractions, and the flexible BCTZ/P(VDF‐TrFE) composite films are prepared using a conventional solution casting process. εr of BCTZ/P(VDF‐TrFE) increases with the mass content of BCTZ, and reaches 23.8 in 20 wt% BCTZ sample. Meanwhile, at a high electrical field of 30 MV/m, the strain and electric field of BCTZ/P(VDF‐TrFE) are in the opposite direction, indicating a negative value of piezoelectric strain coefficient (d33) caused by inverse piezoelectric effect. In addition, d33 of different BCTZ/P(VDF‐TrFE) films are fitted using a strain‐electrical field curve, which firstly increases and then decreases with increases in BCTZ content. As such, a high d33 of −47.3 pC/N is obtained in BCTZ/P(VDF‐TrFE)15/85 wt% film. Thus, this research concerning the inverse piezoelectric effect may provide a reference for designing a piezoelectric composite using in transducers and actuators. [ABSTRACT FROM AUTHOR]

With the advent of the intelligence era, flexible piezoelectric tactile sensors are the key components for sensing information and sending signals. The performance parameters of piezoelectric sensors are closely related to the selection of piezoelectric materials. Compared with conventional piezoelectric materials, polyvinylidene fluoride (PVDF) has significant advantages in flexibility, stretchability, chemical stability, electromechanical conversion, ease of use, and acoustic propagation impedance. As a result, PVDF has become a popular topic of research. This paper introduces the working principle of piezoelectric materials and flexible piezoelectric sensors based on PVDF materials and details the research progress of different materials based on PVDF for the preparation of flexible piezoelectric tactile sensors, such as: PVDF and its copolymers for the preparation of flexible piezoelectric sensors and PVDF doped with other functional materials for the preparation of flexible piezoelectric sensors. In this paper, the advantages and disadvantages of different materials and the development prospects of PVDF flexible piezoelectric sensors are summarized to provide some insights for high‐performance flexible PVDF piezoelectric sensors. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride)/thermoplastic polyurethane (PVDF/TPU) composites filled with carbon‐black polypyrrole were prepared via melt compounding followed by compression molding and fused filament fabrication. CB‐PPy was added to the blends from 0 up to 15% to possible act as nucleating filler for PVDF β phase in order to increase its piezoelectric response. The influence of blending PVDF and TPU and of the addition of CB‐PPy on the overall crystallinity, content of β phase, and piezoelectric response of composites were investigated by differential scanning calorimetry (DSC), Fourier‐transformed infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and determination of the piezoelectric coefficient (d33). It was found that the addition of TPU to PVDF induced an increase of the crystallinity degree and content of β phase in PVDF. Moreover, although the degree of crystallinity of the composites decreased with the addition of CB‐PPy, the percentage of β phase in PVDF was increased. This effect is more significant in samples with filler concentration higher than 6 wt%. As expected, the d33 of the composites increased as the content of the β phase increased. Furthermore, 3D printed samples displayed lower content of β phase and reduced piezoelectric responses when compared to compression molded samples with same composition. [ABSTRACT FROM AUTHOR]

The doped Pb(Zr0.52Ti0.48)O3 system with Nb5+ and Sr2+ were obtained by solid state reactions. The influence of nature of dopants on structural and microstructural properties were analyzed by XRD and SEM techniques and were also investigated the obtained dielectric and piezoelectric properties. The XRD analyzes and the SEM images highlighted the obtaining of homogeneous tetragonal structures, of the perovskite type. The physical (ρa), dielectric constant (ɛr) and piezoelectric (kp) properties of the doped PZT systems were investigated. The Nb5+ doped Pb(Zr0.52Ti0.48)O3 system presented the ɛr = 488 and kp = 0,52. Sr2+ substitution for Nb5+ doped Pb(Zr0.52Ti0.48)O3 reduced the Curie temperature (from 420°C to 360°C), increased the dielectric constant at 1180, and also decreasing the kp (0,39). [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) ceramics possess great potential for practical applications and thus improving their piezoelectric properties is crucial. Pb 0. 9 9 − x Sm 0. 0 1 Ba x Zr 0. 5 3 Ti 0. 4 7 O3 (PSBZT) ceramics with high Curie temperature and excellent piezoelectric properties were fabricated via a conventional solid-state method, and the effect of Ba 2 + doping on the structural, dielectric, piezoelectric and ferroelectric properties was studied in detail. It is shown that doping of Ba 2 + significantly enhanced the piezoelectric properties of PSZT, the maximum d 3 3 ∼ 533 pC/N and T c ∼ 361 ∘ C at x = 0.02 were acquired. Furthermore, PSZT and PSBZT ceramics were used to prepare single element ultrasonic transducers, and their performance were compared and evaluated. The results demonstrate that the PSBZT ceramic-based transducer possesses better sensitivity and bandwidth than the PSZT ceramic-based transducer. [ABSTRACT FROM AUTHOR]

This experimental study investigates the influence of synthetic macro-fibers added in fiber-reinforced concrete (FRC) prismatic specimens on their flexural response and overall cracking performance. Application of a novel structural health monitoring (SHM) system that implements the electromechanical impedance (EMI) technique and the use of piezoelectric lead zirconate titanate (PZT) transducers installed in the FRC prisms are also included. The applied PZT-enabled EMI-based monitoring system was developed to diagnose damage and the overall performance in reinforced concrete (RC) structural members subjected to cyclic repeated loading, simulating seismic excitations in existing RC buildings. The paper also aims to determine the sensitivity of the real-time, wireless, and portable monitoring technique corresponding to the location, the distance, the direction of polarization of the PZT transducers and the location and magnitude of damage due to flexural cracking. Further, the influence of the effect of stresses corresponding at various loading levels and the observed changes in the ΕΜΙ frequency response of the PZT transducers are also examined. Test results indicated that cracking detection is achieved using this SHM system by prompt damage level assessment due to the FRC's flexural load at early seismic loading stages in existing RC buildings. [ABSTRACT FROM AUTHOR]

To improve the machining quality of the non-resonant elliptical vibration cutting (EVC) device, a compound control method for trajectory error compensation is proposed in this paper. Firstly, by analyzing the working principle of non-resonant EVC device and considering the elliptical trajectory error caused by piezoelectric hysteresis, a dynamic PI (Prandtl-Ishlinskii) model relating to voltage change rate and acceleration was established to describe the piezoelectric hysteresis characteristics of EVC devices. Then, the parameters of the dynamic PI model were identified by using the particle swarm optimization (PSO) algorithm. Secondly, based on the dynamic PI model, a compound control method has been proposed in which the inverse dynamic PI model is used as the feedforward controller for the dynamic hysteresis compensation, while PID (proportion integration differentiation) feedback is used to improve the control accuracy. Finally, trajectory-tracking experiments have been conducted to verify the feasibility of the proposed compound control method. [ABSTRACT FROM AUTHOR]

The purpose of this research work was to synthesis bioderived nanocomposite films by incorporating Na0.5Bi0.5TiO3 (NBTO) nanoparticles into a chitosan matrix. The NBTO nanoparticles were synthesized using a traditional solid-state technique. Then, through a solution-casting approach, flexible composite films were fabricated using chitosan polymer. The study presents a range of compelling findings. For structural and morphological insights, scanning electron microscopy (SEM) reveals a fascinating morphology where NBTO nanoparticles are uniformly dispersed and interlocked with other particles, forming interconnected grains with significant interspaces within the chitosan matrix. For the optical properties, the spectral response within the 300–800 nm range is primarily governed by light scattering attributed to NBTO particles with diameter sizes ranging from 100 to 400 nm, as well as the distinctive bandgap exhibited by the NBTO phase. The investigation of dielectric properties demonstrates that composite films exhibit markedly higher dielectric values in comparison to pure chitosan films. It is noteworthy that an increase in the NBTO content results in a corresponding increase in dielectric values, enhancing the versatility of these materials. Local piezoelectric measurements utilizing piezoresponse force microscopy confirm the expected piezoelectric and ferroelectric behavior of NBTO particles when dispersed within the chitosan matrix. This research introduces a novel class of biocompatible nanocomposite materials, combining impressive structural attributes, enhanced dielectric properties, and piezoelectric capabilities. The outcomes of this study hold substantial promise for advanced applications in opto- and piezoelectric technologies, marking a significant advancement in biologically sourced materials with multifunctional properties. [ABSTRACT FROM AUTHOR]

Single-phase ceramic samples of new compositions (Na1 –хSrх)0.5Bi0.5TiO3 (x = 0–0.5), including those modified by additives of SiO2 and ZnO oxides, have been obtained by solid-phase synthesis. The crystal structure and microstructure of these samples, as well as their dielectric, nonlinear optical, and local piezoelectric properties, have been studied. The formation of a perovskite-type phase with a pseudocubic unit cell in all synthesized samples and an increase in the cell volume as a result of partial substitution of perovskite structure cations are established. A decrease in the temperature of ferroelectric phase transitions (confirmed by the methods of dielectric spectroscopy and laser second-harmonic generation) to the tetragonal paraelectric phase is revealed. Remanent piezoelectric hysteresis loops are obtained for the synthesized samples in the polarization switching mode; this result confirms the occurrence of ferroelectric polarization switching. [ABSTRACT FROM AUTHOR]

Two-dimensional gallium nitride (2D GaN) with a large direct bandgap of ~5.3 eV, a high melting temperature of ~2500 °C, and a large Young's modulus ~20 GPa developed for miniaturized interactive electronic gadgets can function at high thermal and mechanical loading conditions. Having various electronic, optoelectronic, spintronic, energy storage devices and sensors in perspective and the robust nature of 2D GaN, it is highly imperative to explore new pathways for its synthesis. Moreover, free-standing sheets will be desirable for large-area applications. We report our discovery of the synthesis of free-standing 2D GaN atomic sheets employing sonochemical exfoliation and the modified Hummers method. Exfoliated 2D GaN atomic sheets exhibit hexagonal and striped phases with microscale lateral dimensions and excellent chemical phase purity, confirmed by Raman and X-ray photoelectron spectroscopy. 2D GaN is highly stable, as confirmed by TGA measurements. While photodiode, FET, spintronics, and SERS-based molecular sensing, IRS element in 6G wireless communication applications of 2D GaN have been demonstrated, its nanocomposite with PVDF exhibits an excellent thermoplastic and piezoelectric behavior. The photodiode, FET, spintronic, piezoelectric, thermoplastic and molecular sensing applications of free-standing 2D GaN synthesized by sonochemical and Hummer's method. [ABSTRACT FROM AUTHOR]

We demonstrate a compact heterodyne Laser Doppler Vibrometer (LDV) based on the realization of optical frequency shift in the silicon nitride photonic integration platform (TriPleX). We theoretically study, and experimentally evaluate two different photonic integrated optical frequency shifters (OFSs), utilizing serrodyne and single-sideband (SSB) modulation. Both OFSs employ stress-optic modulators (SOMs) based on the non-resonant piezoelectrical actuation of lead zirconate titanate (PZT) thin-films, deposited on top of the silicon nitride waveguides with a wafer-scale process. To improve the modulation bandwidth of the SOMs we investigate a novel configuration of the electrodes used for the actuation, where both electrodes are placed on top of the PZT layer. Using this top-top electrode configuration we report frequency shift of 100 kHz and 2.5 MHz, and suppression ratio of the unwanted sidebands of 22.1 dB and 39 dB, using the serrodyne and the SSB OFS, respectively. The best performing SOM structure induces 0.25π peak-to-peak sinusoidal phase-shift with 156 mW power dissipation at 2.5 MHz. We use the SSB-OFS in our compact LDV system to demonstrate vibration measurements in the kHz regime. The system comprises a dual-polarization coherent detector built in the PolyBoard platform, utilizing hybrid integration of InP photodiodes (PDs). High quality LDV performance with measurement of vibration frequencies up to several hundreds of kHz and displacement resolution of 10 pm are supported with our system. [ABSTRACT FROM AUTHOR]

The solar‐only response nature limits the luminescent solar concentrators (LSCs) to solar harvesting rather than responding to other stimuli, which restricts the role of LSCs to energy supply in self‐powered internet of things (IoT) systems, and the application potential of LSCs in self‐powered devices has been seriously overlooked. In this work, LSCs with photovoltaic and piezoelectric features are proposed for the first time, extending the application scenario of LSCs to self‐powered sensors with pressure responsiveness. The luminescent layer of perovskite‐polymer composite film is prepared via in situ blade coating with the piezoelectric polymer matrix of poly(vinylidenefluoride‐trifluoroethylene) (P(VDF‐TrFE)). P(VDF‐TrFE) possesses stronger DMF adsorption capacity and higher electroactive phase content than a conventional piezoelectric matrix of poly(vinylidene fluoride) (PVDF), which not only reduces the residual‐solvent‐induced defects in perovskite luminophores, but also brings a sensitive pressure response to LSCs. The dual‐functional LSCs achieve a power conversion efficiency of 1.01% and a output piezoelectric voltage of 0.95 V can be obtained even at a low pressure of 0.16 kPa. A self‐powered speed measurement system is demonstrated, and the actual speed measurement is carried out. Such dual‐functional LSCs show great potential in self‐powered electrical devices, which can be applied to low‐energy‐consumption IoT systems and other commercial smart home products. [ABSTRACT FROM AUTHOR]

Real-time condition monitoring of various types of machinery using sensor technology has gained significant importance in recent years. However, relying on batteries to power these sensors proves to be sub-optimal, as it necessitates regular charging or replacement. To address this, harvesting waste energy from ambient sources emerges as a more efficient alternative. Everyday applications like vehicle wheels, fans, and turbines present ambient sources of waste rotational energy. In this study, we propose a novel rotational energy harvester design that converts rotational energy into linear energy. This linear energy impacts a piezoelectric disk, generating an electric potential. Through simulations, the expected electric potential at varying frequencies was evaluated. Subsequently, experimental tests were conducted by connecting the harvester to a rectifier for AC-to-DC signal conversion and an oscilloscope for voltage measurement. A DC motor replicated the rotational motion at the frequencies from the simulation, and the power output was measured. Using the power transfer theorem, simulation and experimental power outputs were calculated, resulting in values of 188, 513, and 1293 μW and 88.89, 336, and 923 μW, respectively. These results reveal that the designed harvester is competitive with those of existing rotational energy harvester designs, demonstrating the promising potential of this novel harvester. [ABSTRACT FROM AUTHOR]

The detection and location of pipeline leakage can be deduced from the time arrival leak signals measured by acoustic sensors placed at the pipe. Ongoing research in this field is primarily focused on refining techniques for accurately estimating the time delays. This enhancement predominantly revolves around the application of advanced signal processing methods. Additionally, researchers are actively immersed in the utilization of machine learning approaches on vibro-acoustic data files, to determine the presence or absence of leaks. Less attention has been given to evaluating the sensitivity, performance, and overall effectiveness of these sensors in leak detection; although acoustic methods have been successfully used for leak detection in metallic pipes, they are less effective in plastic pipes due to the high attenuation of leak noise signals. The primary thrust of this research centers on identifying sensors that not only possess sensitivity but also exhibit high efficiency. To accomplish this goal, we conducted an exhaustive evaluation of the performance of three distinct categories of acoustic sensors employed for detecting water leaks in plastic pipes: specifically, lead zirconate titanate (PZT) sensors, polyvinylidene fluoride (PVDF) sensors, and surface acoustic wave (SAW) sensors. Our evaluation encompassed the performance of PVDF and SAW sensors in leak detection, comparing them to PZT sensors under a variety of conditions, including different leak sizes, flow rates, and distances from the leak. The results showed that all three sensors, when they were placed in the same position, were able to detect water leaks in plastic pipes with different sensitivities. For small leaks (1 mm, 2 mm), the PVDF sensor showed the greatest sensitivity (0.4 dB/L/h, 0.33 dB/L/h), followed by the SAW sensor (0.16 dB/L/h, 0.14 dB/L/h), and finally the PZT (0.13 dB/L/h, 0.12 dB/L/h). Similarly, for larger leaks (4 mm, 10 mm), the PVDF sensor continued to show superior sensitivity (0.2 dB/L/h, 0.17 dB/L/h), followed by the SAW sensor (0.13 dB/L/h, 0.11), and finally the PZT sensor (0.12 dB/L/h, 0.1 dB/L/h), outperforming the PZT sensor. This suggests that SAW and PVDF sensors, have the potential to serve as valuable, cost-effective alternatives to traditional commercial leak noise transducers. The outcomes of this comparative study involving three acoustic sensors hold the potential to advance the development of robust and dependable systems for the detection of water leaks in plastic pipelines. [ABSTRACT FROM AUTHOR]

Bandgaps of traditional phononic crystals (PCs) are determined using structural geometric parameters and material properties, and they are difficult to tune in practical applications. Piezoelectric PCs with lead zirconium titanate piezoelectric ceramics (abbreviated to piezoelectric PCs) have multi-physics coupling effects and their bandgaps can be tuned through external circuits to expand the application range of the PCs. First, the typical structures of piezoelectric PCs are summarized and analyzed. According to the structure, common tunable piezoelectric PCs can be roughly divided into three categories: PCs that only contain piezoelectric materials (single piezoelectric PCs), PCs composed of embedded piezoelectric materials in elastic materials (composite piezoelectric PCs), and PCs that are composed of an elastic base structure and attached piezoelectric patches (patch-type piezoelectric PCs). Second, the tuning methods of bandgaps for piezoelectric PCs are summarized and analyzed. Then, the calculation methods of the bandgaps of piezoelectric PCs are reviewed and analyzed. Finally, conclusions are drawn on the research status of piezoelectric PCs, shortcomings of the existing research are discussed, and future development directions are proposed. [ABSTRACT FROM AUTHOR]

In this study, the characteristics in the lead-free piezoelectric ceramic 0.5Ba(Zr0.2Ti0.8)O3−0.5(Ba0.7Ca0.3)TiO3 (0.5BZT–0.5BCT) were investigated to assess its potential for Rosen-type piezoelectric transformers. This piezoelectric ceramic has a piezoelectric charge coefficient d33 of 430 pC/N, an electromechanical coupling factor kp of 49%, a dielectric constant εr of 2836, a remnant polarization Pr of 4.98 μC/cm2, and a coercive electric field Ec of 2.41 kV/cm. Sb2O3 was soft doped with 0.05, 0.1, 0.15, and 0.2 mol%, respectively, and exhibited excellent physical properties at 0.1 mol%. Based on this, a piezoelectric transformer was fabricated and measured, and it showed better output characteristics than pure 0.5BZT–0.5BCT. The amplification ratio (Vout/Vin) was optimized based on the device geometry and properties of the piezoelectric material. Moreover, the output characteristics of the Rosen−type piezoelectric transformer were simulated with the PSpice program. Output values of the fabricated and simulated piezoelectric transformers for the r vibrational frequency were compared and analyzed. Accordingly, the step-up amplification ratios Vout/Vin of the fabricated and simulated devices at the vibrational frequency were compared as well. This piezoelectric transformer could replace silicon steel transformers and be used for the creation of black light and for laptop chargers. [ABSTRACT FROM AUTHOR]

This paper describes a study that focuses on assessing the influence of composites with different thicknesses (2 mm, 4 mm, and 9 mm) on embedded ultrasonic guided waves (UGWs) under varying temperatures. The study also demonstrates the effectiveness of these embedded sensors in identifying damage. A novel cut-out method that included an embedded diagnostic layer and phased-array lead zirconate titanate (PZT) transducers, created using the ink-jet printing technique in the manufacturing process was employed. The research then focused on studying the behavior of UGWs under varying temperatures for each composite panel. This analysis aimed to understand how temperature variations affected the propagation of guided waves in thick composites. Finally, artificial damage on the surface and impact damage were introduced, both embedded and surface-mounted PZT transducers were used to detect and locate these damages in different thickness composite panels. The results of damage localization indicated that the embedded PZT transducers were more sensitive than the surface-mounted transducers in locating the damage in thick composites. [ABSTRACT FROM AUTHOR]

This work presents the impact generated energy harvesting characteristics of cement/lead zirconate titanate (Pb(Zr0.52Ti0.48)O3; PZT) composites. A soft grade PZT (SP 5 A) with ∼1 µm sized particles in an unpoled state was utilised to prepare cement/PZT composites. The experiments were performed on 28 days' water cured unpoled samples. The total cumulative volume and average pore radius are observed to decrease with PZT concentration in the composite. The values of piezoelectric coefficient and capacitance were, respectively, found to increase by 300 and 275% for cement/PZT composites consisting of 40% PZT compared to that of 5% added PZT. The impact generated voltage and energy increases significantly with increasing PZT-content. The voltage generation from cement/PZT could be because of the oscillations of dipoles and the mobility of ions in the pores of the hydrated cement. The results obtained foreshadow the prospect of utilising cement/PZT composites for energy harvesting from civil structures, structural health monitoring, and as sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] Bulk piezoceramics are widely used and functional materials, but they are hard to be shaped to adapt to complex 3D surfaces. Most existing ceramic shaping techniques, like 3D printing, come at the cost of physical properties such as piezoelectricity and thermal stability. Here to fabricate 3D piezoceramic sheets, we report a mold-assisted sintering (MAS) method that can replicate 3D surfaces with nonzero Gaussian curvatures while maintaining the intrinsic properties. Assisted with supporting molds, the MAS exploits elastic-to-viscous transition of piezoceramic powder compacts during sintering, bypassing the boundaries of deformation and surface development in an elastic continuum. We successfully replicate shapes to sintered lead zirconate titanate (PZT) ceramics from designed molds with saddle, sine and spherical surfaces, respectively. The PZT ceramic replicas show high piezoelectricity and excellent conformability towards nonplanar surfaces (maximum deviation 90 μm). We further demonstrate the advantage of the conformal curved piezoceramics by using them for wirelessly transferring power over a pipeline. The MAS method is low-cost, simple, scalable and applicable to various 3D energy transducers. [ABSTRACT FROM AUTHOR]

In this work, the random electric fields are constructed in the hard PZT ceramics by adding the ZnO particles as a secondary phase to tune the piezoelectric properties and losses. It is found that the internal bias electric field existing in the hard PZT ceramics has been tuned successfully by the random electric fields and its value reduces with the increased ZnO content. As a consequence, the piezoelectric constant d33 reaches up to 483 pC/N in the PZT/0.75 wt%ZnO composite, which is much higher than that of the hard PZT matrix. In the meantime, the electromechanical quality factor Qm, dielectric loss tan δ, and Curie temperature TC for this composite are about 1109, 0.55%, and 279°C, respectively. The promoted d33 is attributed to the small domain size and reduced internal bias electric field, whereas the low losses (large Qm and low tan δ) can be put down to the still existing nonzero internal bias electric field. [ABSTRACT FROM AUTHOR]

This paper presents the results of experimental research focused on wave energy harvesting and its conversion to power Internet of Things (IoT) devices. The harvesting and conversion process was performed using a wave energy converter (WEC) consisting of a lead zirconate titanate piezoelectric ceramic perovskite material and a prototype power electronic circuit. The designed WEC was considered as a power supply for an end node device (END) of an IoT network. The END consisted of a long-range radio module and an electronic paper display. A set of physical experiments were carried out, and the results confirmed that an energy surplus was supplied by WEC compared to the energy consumed by the END. Hence, the proposed scheme was experimentally validated as a convenient solution that could enable the autonomous operation of an IoT device. The use case presented here for the proposed WEC was analysed for selected sea areas on the basis of wave statistics. The novelty of this paper arises from an investigation that confirms that WECs can significantly contribute to the development of wireless and mobile IoT communication powered by freely available sea wave energy. [ABSTRACT FROM AUTHOR]

BaTiO3/cement pyroelectric composite was fabricated and it was also explored for pyrocatalysis dye degradation at room temperature. The BaTiO3/cement was electrically poled and piezoelectric coefficient was found to be ±20 pC/N. Poled BaTiO3/cement composite can effectively decompose Rhodanmine B dye with a degradation efficiency of 60% by harvesting 6–40 °C cold–hot alternation energy. These results along with the high stability displayed by the composites indicate a new approach for development of functional cements for environmental remediation. [ABSTRACT FROM AUTHOR]

Research of piezoelectric ceramics via DLP technology has drawn considerable interest due to its high geometrical flexibility. However, the poor curing properties limit the use of DLP technology to fabricate piezoelectric ceramics. Herein, we overcome this challenge in prepared lead zirconate titanate (PZT) piezoelectric ceramics via DLP technology by incorporating ultralow refractive index and ultraviolet light absorptivity of soluble starch in PZT ceramic slurry. After the post-process, the relative density of printed PZT ceramic with 20 vol% soluble starch could reach about 89.51% of theoretical density. The printed PZT ceramic exhibits remarkable dielectric permittivity, remnant polarization, piezoelectric strain constant, piezoelectric voltage constant, figure of merit and electromechanical coupling factor of 2196, 35.56 μC/cm2, 373 pC/N, 1.92 × 10−2 Vm/N, 7.16 × 10−12 m2/N and 42.28%, respectively. The results achieved in this research indicate that our work provides a promising route for fabrication of advanced ceramics with high performance and designed complex structures by digital light processing. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT)-based piezoelectric ceramics are important functional materials for various electromechanical applications due to their excellent performance and temperature stability. Herein, the rhombohedral PbZr 0.55 Ti 0.45 O 3 ceramics with increasing average grain size from 3.57 μm to 10.85 μm were prepared by a conventional solid-state reaction method. The grain-size dependent dielectric, ferroelectric and piezoelectric properties were systematically investigated. With the increasing grain size, a significant softening effect with enhanced electromechanical properties was observed. Results of piezoresponse force microscopy show that the formation of non-180° domain walls was strongly repressed in the fine-grain samples, resulting in decreased domain wall mobility. Meanwhile, a noteworthy hardening effect was also observed in the coarse-grain samples with high domain wall mobility, which may be related to the enhanced bulk effect with increasing grain size. The results of this work confirmed that grain size engineering is an effective strategy for designing piezoelectric materials with excellent combination properties. [ABSTRACT FROM AUTHOR]